Injection nozzle for internal combustion engines



May 11, 1937. K. scHwAlGl-:R 2,080,189

INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES Filed Aug. 14, 1933 2 Sheets-Sheet l INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES Filed Aug. 14, 1933 2 Sheets-Sheet 2 Emi nvenor 'of combustion gases.

'mesas May 11, 1937 UNITED sTATEs PATENT oEFlcE INJECTION NOZZLE FOB INTERNAL COMBUSTION ENGINES Karl Schwaiger, Gaggenau/Baden, Germany, as-

signor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany, a company of Germany Application AugustM,

isaaserlax No. esmas In Germany August 17, 1932 11 Claims.

'I'his invention relates to an arrangement of injection nozzles for internal combustion engines.

more particularly for high speed Diesel engines and .consists substantially in this, that an intermediate piece disposed between the nozzle body and the combustion space, which is made of a material that is a particularly good heat conductor and which is in heat-conductive connection with the surrounding wall, partially or entirely screens the nozzle body with respect to the combustion space or prevents any considerable heat accumulation in the nozzle body. A suitable material for the intermediate piece is copper or the like, which is also capable of plastic deformation, so that the nozzle will bear perfectly tightly against the intermediate piece, the latter being preferably inserted with a conical surface in the wall of the cylinder head. The invention also provides for a particularly suitable and effective cooling of the parts in question. f

The nozzle arrangements as hitherto known do not adequately satisfy the thermal requirements.

The higher the speed` of revolution of the en-l gine, however, the greater the importance of taking the thermal conditions into account. In order to prevent an overheating of the nozzle at these high speeds oi revolution, it is essential that provision be made for an eiective regulation or conduction of the heat from the nozzle body.

More particularly the arrangement should also be made such that on the one hand the heat of combustion is kept away from the lower nozzle surface, which as a rule is substantially exposed towards the combustion space, and that on the other hand the annular gap between nozzle body and cylinder head or cap nut, which is normally provided among other reasons for avoiding stresses, shall be as small as possible and shall be packed to prevent the penetration 'I'hese two requirements are best fuliilled Iby a copper ring.

It has furthermore been found that the screening action is most eiective, if the copper disc rests rmly on the lower nozzle surface and there' (Cl. 12S-312) been reached, a state of equilibrium is obtained. At the same time no substantial pressure is exerted by the copper disc on the nozzle surface as might at first be expected, as in pressing the nozzle body into the copper disc it is actually 5 a question of a plastic and not of an elastic change of shape of the copper. Any tension between the copper and the nozzle will be with certainty equalized the iirst time the engine is put in operation, more particularly for the reason l0 that the copper when heated becomes more plastic. Preferably the surface which is exposed to the combustion gases is kept as small as possible and the heat absorbed is conducted away by means of the good conductivity of copper l5 through its large cross-section to the cap nut.

The provision of such intermediate pieces has in practice provided astonishingly favorable results. While with the arrangements hitherto used the nozzle valve always fused into the nozzle 20 body, it has been found that after the insertion of the intermediate pieces anyfusing of the valve needle is practically completely avoided.

In the accompanying drawings several constructional examples of the invention are shown 25 in Figs. 1-4.

In Figs. 1 and 2of the drawings a is the cylinder head with the cooling water space b. Into a suitable bore in the cylinder head, which extends through the cooling water space, a sleeve 30 c is inserted in a known manner, which also contains the precombustion chamber e which communicates with the main combustion space, for instance by means of an insertion piece d with throttle openings and a core piece. In tliis 35 sleeve is disposed the injection nozzle f with the sleeve-shaped cap nut g surrounding it, an intermediate piece h. suitably of copper being provided between the nozzle end and the cap nut on the one hand and a collar. c1 of the sleeve 40 c on the other hand.

This intermediate piece is in the form of an annular disc, which bears with a conical seating surface against the collar c1 and projects under the nozzle en'd in such a manner that there 45 only remains in the nozzle axis an opening i which is adapted to the fuel jet. In the rst place there is provided between the cap nut and thedisc (before theflrst assemblage) a slight clearance k of for instance 0.1 mm., which dis- 50 appears yin the manner described, on the nozzle being tightened.

In the arrangement shown in Fig. 2 only the sleeve c is directly swept over by the cooling water. If the heat is to be conveyed away more 55 2 effectively, more particularly in the case of speeds of over 2,000 revolutions per minute, an arrangement such as that shown in Fig. 1 may be adopted. The heat is conveyed away from the copper disc in this case in a very effective manner by direct water cooling. Through adopting a suitable cross-section of the copper an unhindered ow of heat can be obtained. In this case the cooling Water is conveyed through openings m in the precombustion chamber sleeve c and through openings n in an intermediate sleeve o (which may for instance be made integral with the copper ring),- which admit the cooling water to the copper ring and to the cap nut. In special cases the cap nut might also be provided with transverse bores, so that-the nozzle body will itself stand in the cooling water and any accumulation of heat will be avoided.

In Figs. 3 and 4 two further constructional examples of the screening of the nozzle or of the nozzle gap surrounding the nozzle body ane shown.

In the cylinder head a with the precombustion chamber e there is inserted the nozzle body' f containing the nozzle needle f' into the nozzle nut g withva gap p. 'Ihe lower open end of this gap communicates with the precombustion chamber e, so that the nozzle body is centered only in its .upper part which is not seriously aected by the heat of combustion and no stresses due to the tightening and to the action of heat can occur in the nozzle body.

According to the'invention in .the example shown in Fig. 3 a sheet metal covering ring q is disposed in front of the end of the gap p, which for instance as shown in the drawings may be fixed to the nut g or to the nozzle body or the like in any suitable manner, and which extends below the gap in such a manner that the combustion gases can no longer pass directly from the precombustion chamber or the combustion space into the gap. A sort of labyrinth packing thus results, and it has been found that in some cases such screening means will be sufficient for preventing the nozzle body from becoming incandescent or sooted up.

In Fig. 4 the gap p is completely closed to the combustion space or the precombustion chamber by a packing r, which is inserted for instance between the nozzle body and a flange on the nut g.

The invention is also applicable to other accessory parts which are connected in a similar manner as the injection nozzle with the combustion space.

What I Vclaim is:

1. In a Diesel engine having a combustion space and a wall with a bore therein in open communication with the combustion space, a

fuel injection nozzle having an injection open' ing at one end arranged in said bore for injecting fuel into the combustion space, said wall ya iiange-like projection extending infwardlyfrom the said bore between the end of the oz'zle having the injection opening and the combustion chamber, a sleeve in said bore surrounding the injection nozzle and a substantially annular deformable intermediate piece arranged in the bore between the ange-like projection and the end of the nozzle having the injection opening, and the corresponding end of the sleeve, the

- inner diameter of the intermediate piece being smaller than the said end of the nozzle so as to screen part of said end from the combustion space, the fuel injection nozzle being applied to 4said wall having a ange-like projection extending inwardly from the said bore between the end of the nozzle having the injection opening and the combustion chamber and a substantially annular intermediate piece arranged in the bore between the ange-like projection and the end of the nozzle having the injection opening, the inner diameter of the intermediateapiece being smaller than the said end of the nozzle but larger than the diameter ofthe injection opening so as to screen part of said end from the combustion space, the fuel injection-nozzle being applied tothe intermediate piece under pressure so as to produce a certain amount of deformation of the intermediate piece. f

3. In a Diesel engine having a combustion space and an` externally cooled wall with a bore therein in open communication with the combustion space, a fuel injection nozzle having an injection opening at one end arranged in said bore Y for injecting fuel into the combustion space, said wall having a flange-like projection extending inwardly from the said bore between the end of the nozzle having the injection opening and the combustion chamber and a substantially annular copper intermediate piece arranged in the bore between the flange-like projection and the end of the nozzle having the injection opening, the inner diameter of the intermediate piece being smaller than the said end of the nozzle but larger than the diameter of the injection opening so- A as to screen part of said end from the combustion space, the fuel injection nozzle being applied to the intermediate piece under pressure so as to produce a certain amount of deformation of the intermediate piece.

4. In a Diesel engine, the combination as set forth in claim 2 in which the intermediate piece has a conical end surface facing towards the combustion space and the flange-like projection has a corresponding conical inner surface.

5. In a Diesel engine, the combination as set forth in claim 2 with means for supplying cooling water to the wall and conduits in communicatlonjtherewith for allowing direct access of cooling water to the intermediate piece.

6. In a Diesel engine having a combustion space and a wallwith a bore therein in open communication with the combustion space. a fuel injection nozzle having an injection opening at one end arranged in s'aid bore for injecting fuel into. the combustion space, said wall having a flange-like projection extending inwardly from the said bore between the end of the nozzle having the injection opening and the combustion chamber, a sleeve in saidv bore surrounding the injection nozzle and a substantially annular" space, the fuel injection nozzle protruding slightly beyond the end of the sleeve adjacent said deformable intermediate piece. so as to deform said intermediate piece on being applied to the i latter.

7. In a Diesel engine having a combustion space and a wall with external cooling means therefor, said wall having a bore therein in open communication with the combustion space, a

l) fuel injection nozzle having an injection opening at one end and arranged in said bore for injecting fuel into the combustion space. an injection valve in said nozzle for opening and closing said injection opening. guiding means for said injec- 5 tion valve in the end of the nozzle having the injection opening, a substantially annular discshaped intermediate piece arranged between the said end of the injection nozzle and the combustion space in close contact with the end of the nozzle and with said wall, said intermediate piece having a smaller internal diameter than that of the end of the injection nozzle but greater than that of the injection opening, so as to permit of an unrestricted and rapid flow of heat r from the end of the nozzle through the intermediate piece to the said wall.

8. In a Diesel engine, the combination as set forth in claim 'I in which the intermediate piece is of copper.

9. In a Diesel engine having a combustion space and a wall with external cooling means therefor, said wall having a bore therein in open communication with the combustion space with an inwardly extending abutment, a iuel injection nozzle having an injection opening at one end and arranged in said bore for injecting fuel into the combustion space, an injection valve in said nozzle for opening and closing said injection opening, guiding means for said injection valve in the end of the nozzle having the injection opening, a substantially annular disc-shaped intermediate piece arranged between the said end of the injection nozzle and said abutment in close contact with the end of the nozzle and with saidwall and abutment, said intermediate piece having a smaller internal diameter than that of the end of the injection nozzle but greater than that of the injection opening. sons to permit of an unrestricted and rapid flow of heat from the end of the nozzle through the intermediate piece to the said wall.

10. In a Diesel engine. the combination as set forth in claim 9 in which the intermediate piece on the side thereof remote from the injection nozzle is conical so that its external diameter diminishes towards the combustion chamber, the surface of the abutment in contact with the intermediate piece having a corresponding conical shape.

11. In a Diesel engine, the combination as set t forth in claim 'I with means for supplying cooling fluid to the wall and a conduit in communication therewith for supplying cooling fluid directly to the intermediate piece.

KARL SCHWAIGER. 

